SE522829C2 - Multiple-band antenna for use in portable telecommunication apparatus to establish and maintain wireless radio links using continuous trace with portions in different planes - Google Patents

Abstract

A multiple-band antenna (11) consists of a continuous trace of electrically conductive material and the antenna is connected by a connector (12) to the radio circuitry (9) provided on a printed circuit board (10) in a mobile telephone. The trace has a first conductive portion (13) in a first plane and a second conductive portion (15,16) in a second different plane. AN Independent claim is included for a portable telecommunication apparatus.

Description

25 30 35 522 8 UEUSIS AR \\ CURRENT \ DB \ PMDIi <\ DOC \ P \] | l7U-0] | '41 | SE-doc vb -. | a n nu o v. n -. . . ,. f »a.

E on a first surface of a dielectric plate. On an opposite surface of the dielectric plate there is a flat parasitic element, which in some embodiments can function as a separate radiator, whereby the antenna is provided with the possibility of operating in three frequency ranges. The antenna according to EP-A2-0 923 158 is specially adapted for mounting on the rear wall of the mobile phone.

US-A-6 124 831 discloses a folded dual frequency band antenna for a wireless communicator. A C-shaped dielectric base has a folded configuration. A continuous loop of conductive material, which serves as a radiating element, is placed on the first and second opposite and parallel surfaces of the dielectric substrate. Between the first and second portions of the continuous loop of conductive material, which are placed on two parallel surfaces of the dielectric substrate, there is an elongated dielectric spacer. The first part of the continuous loop of conductive material is further electrically connected to the second portion through an intermediate portion of conductive material, which is located on a third surface of the dielectric substrate, perpendicular to the first and second the surfaces. The antenna provides at least two separate and distinct frequency bands. The continuous loop of conductive material, which is located on the first, second and intermediate third surfaces of the dielectric substrate, has a uniform meander shape with identical configuration and loop width.

SUMMARY OF THE INVENTION It is a primary object of the present invention to provide a significant improvement over prior art antennas of the type having a loop of thin conductive material which is adapted to operate in more than one frequency band. More specifically, it is an object of the invention to provide an antenna which is both small and small. SE-dßt ø -. ~ .- n u.

. '. OII il has good performance not only in a low frequency band, such as the 900 MHz GSM band, but also good performance in several higher frequency bands, such as the 1800 MHz GSM or DCS band, 1900 MHz GSM or PCS band, 2.1 GHz The UMTS band as well as the 2.4 GHz ISM band (Bluetoothæ).

A further object is to provide an antenna which can be designed as a continuous loop of conductive material without the need for separate parasitic elements for impedance matching purposes.

A further object of the invention is to provide an antenna which does not require a well-defined electrical ground. Yet another object is to provide an antenna which is inexpensive to manufacture.

Finally, a further object is to provide an antenna which can be enclosed in a plastic or rubber housing, which can be attached to an external portion of the mobile telephone and which can be bent, to some extent, without damaging the antenna.

The above objects are achieved with a multiband antenna according to the appended independent requirement. The objects are more specifically achieved by a multi-band antenna of the type comprising a continuous loop of conductive material with a first conductive portion arranged in a first plane and a second conductive portion arranged in a second plane, which first and second planes are different from each other, where the first conductive portion has a supply end to be connected to radio circuit systems in a portable telecommunication apparatus by arranging the second conductive portion so that it has a distinctly smaller width than the first conductive portion.

According to a preferred embodiment, the above objects are further achieved by constructing the first conductive portion as a wide rectilinear feed strip while the second conductive portion is given a meander shape with a substantially narrower width. The first and second leading parties 10 15 20 25 30 35 522 020513 AR \\ (URRE || T \ DB \ PuhlíC \ DOC \ P \ J | B7'O-OI \ II SE-doc v. -. N u. I. The distinct change of width between the first conductive portion (the wide supply strip) and the intermediate third conductive portion generates an impedance block, which plays an important role in the electrical performance.

In the preferred embodiment, the first and second conductive portions (ie the first and second parallel planes) are advantageously offset by at least 2 mm (equal to the length of the intermediate third conductive portion), which limits parasitic effects between the first and second leading parties. The preferred embodiment further has a fourth conductive portion, which is attached to the end of the second conductive portion (the narrow meander-shaped portion), and which is substantially wider than the second conductive portion and acts to provide capacitive load on the antenna for tuning purposes. The first conductive portion (the wide feed strip) has a large width, which makes it significantly wider than conventional antenna loops of conductive material. In the preferred embodiment, the width of the first conductive portion is at least 5 mm, and this includes the supply interface to the radio circuit system of the portable telecommunication apparatus.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of preferred and alternative embodiments, from the following drawings as well as from the subclaims.

It should be noted that the term "comprising" when used in this detailed description is to be taken to specify the presence of stated features, wholes, steps or components but does not exclude proximity. . | - ao u ~. , ,, 020513 AR \\ CURRENT \ DB \ Public \ DOC \ P \ l67N-GLUI SE-d0C. ,,,, _ _ _ _ '_ ... u the existence or addition of one or more other features, wholes, steps, components or groups thereof.

Brief Description of the Drawings Preferred and alternative embodiments of the present invention will now be described in further detail with reference to the following drawings, in which: Fig. 1 is a schematic perspective view of a portable telecommunication apparatus in the form of a mobile telephone according to an aspect of the invention, FIG. 2 is a side view of the mobile telephone, shown in FIG.

Fig. 3 is a schematic perspective view of a multi-band antenna according to a preferred (first) embodiment of the invention, which is connected to a radio circuit system on a printed circuit board in the mobile telephone of Figs. 1 and 2, Fig. 4 is a side view corresponding to Fig. 3, Figs. Fig. 5 is an enlarged top view of the multiband antenna indicated in Figs. 3 and 4, Fig. 6, a side view and an enlarged top view of a second embodiment 7 and 8 illustrate a schematic perspective view of the present invention; Fig. 12-14 illustrates a schematic perspective view, a side view and an enlarged top view of a third embodiment of the invention, FIGS. 12-14 illustrate a schematic perspective view, a side view and an enlarged top view of a fourth embodiment of the present invention, which is based on practical tests, FIG. Fig. 15 is a reflection attenuation diagram to illustrate simulated performance of the first, second and third embodiments; Fig. 16 is a Smith diagram representing simulated pr. stand for the first embodiment, 10 15 20 25 30 Cf) fi .J¿.¿. . . . "020513 AR \\ CURRENT \ D8 \ Pub1ic \ DOC \ P \ lB? '| -UL'll SE-dø fi q I c u o n u - 1: a.

Fig. 17 is a Smith diagram representing simulated performance of the second embodiment, Fig. 18 is a Smith diagram representing simulated performance of the third embodiment, Fig. 19 versus frequency for the third embodiment, Fig. 20 versus frequency for the third embodiment, Fig. 21 efficiency Fig. 22 is a standing wave ratio diagram for voltage illustrates circular polarization gain illustrates linear polarization gain illustrates antenna efficiency and radiation for the third embodiment, (VSWR diagram) having the a rubber housing and held in free space, FIG. 23 is a Smith diagram illustrating measured antenna performance for the fourth embodiment when the antenna has a rubber housing and is held in free space, FIG. , which represents the measured antenna performance for the fourth embodiment nä The antenna has a rubber housing and is held in position to speak, and FIG. 25 is a Smith diagram illustrating measured antenna performance for the fourth embodiment when the antenna has a rubber housing and is held in a position to speak.

Detailed Description Figures 1 and 2 illustrate a mobile telephone 1 as an example of a portable telecommunication apparatus in which the antenna according to the invention can be used. However, the antenna according to the invention can be used in essentially any other portable communication device, which must operate in at least two, preferably at least three frequency bands. 10 15 20 25 30 35 I? h OALL 020513 AR \\ CURRENT \ DE \ PUBIic \ D0 (\ P \ l! 7'4- fl1'4 l SE-dnc VD n | ao. N ovo ø n | u.,, ,,: sn C) ¿ The mobile telephone 1, which is shown in FIGS. 1 and 2, comprises a loudspeaker 2, a keypad 4, a microphone 5 and a display, as is generally known in the art. The mobile telephone 1 further comprises a plastic or rubber housing 3, which is mounted on top of the device housing of the mobile telephone 1. The antenna according to the invention is enclosed within this housing, as will be described further below. As shown in particular in FIG. 2, the plastic or rubber housing 3 has some flexibility (as indicated by reference numerals 6 and 7) so that the antenna housing 3 can be bent, to some extent, without damaging the antenna inside the housing. This obviously provides a great advantage over conventional mobile telephones of the type having either a retractable rod antenna or an inflexible helix antenna, both of which are substantially unprotected and may be inadvertently interrupted in unfortunate situations where the antenna is exposed to strong external breaking forces.

Figs. 3-5 illustrate a multiband antenna 11 according to a preferred (first) embodiment of the invention. The antenna 11 consists of a continuous loop of electrically conductive material, preferably copper or other suitable metal with very good conductive properties. The conductive material is very thin, preferably about 30-35 microns; consequently, the thickness of the antenna 11 has been greatly exaggerated only for illustrative purposes in the drawings. As shown in Figs. 3-5, an antenna connection part 12 serves to connect the antenna 11 to the radio circuit system 9, which is provided on a printed circuit board 10 in the mobile telephone 1. The antenna connection part 12 is only schematically indicated in Figs. 3-5. It can be implemented through any of a plurality of commercially available antenna connection members, such as a resilient connector or a pogo-pin connector.

The radio circuit system 9 as such does not otherwise constitute a significant part of the present invention and will therefore not be described in further detail herein.

As will be readily appreciated by those skilled in the art, radio circuit systems will be used. . 9 includes various known HF (high frequency) and baseband components suitable for receiving a radio frequency (HF) signal, filtering the received signal, demodulating the received signal into a baseband signal, filtering the baseband signal further, convert the baseband signal to digital form, apply digital signal processing to the digitized baseband signal (including channel and speech decoding), etc. to be transmitted, modulate it on a carrier signal, provide the resulting HF signal to the antenna 11, etc.

The antenna loop 11 essentially forms a biplanar structure 17), which is arranged at a vertical distance of about 5-10 mm (a first plane 13 and a second plane 15, 16, with respect to the printed printed circuit board 10. The plane of the antenna loop 11 can either be parallel to the printed printed circuit board 10, as shown in the drawings, or to the printed printed circuit board 10 depending on the actual implement- alternatively arranged at an angle, such as 15 °, the ring, the construction of the housing 3 with respect to the mobile phone 1 device housing etc. The first and second antenna planes are furthermore preferably, but not necessarily, parallel to each other.

The antenna loop 11 comprises a first conductive portion 13, which acts as a geometrically wide feed strip and is consequently adapted to communicate electrically with the radio circuit system 9 on the printed circuit board 10 via the antenna connection portion 12. The first conductive portion 13 has a rectilinear extent, as shown in FIG. -5, and has a substantial width of several mm, preferably 5-7 mm.

However, the exact value of the width of the first conductive portion 13 must be selected with mature consideration of various design and setting parameters, as will be readily understood by those skilled in the art. The first leading portion 13 (the 10 15 20 25 30 35 I 'f \ f \ O¿! ¿020513 AR \\ CURRENT \ DB \ Puh1iC \ DOC \ P \ 167H-DINI SE.d0C Ann Ö4 fl7 5 wide feed strip) will primarily act as a radiator such as DCS, PCS, UMTS or Blueto- othm, as will be described in further detail later- for higher frequency bands, re.

A second conductive portion 15, 16 of the continuous antenna loop 11 will primarily function as a radiator for a low frequency band such as GSM 900. As shown in Figs. 3-5, the second conductive portion 15, 16 is rotated in a meander shape (with the exception of a short initial straight part 15) and has a significantly smaller (narrower) width than the first conductive portion 13 - a factor of 1:10 is a suitable example.

The first conductive portion 13 is arranged in a first horizontal plane, while the second conductive portion 15, 16 is arranged in a second horizontal plane, and the first and second conductive portions are interconnected via a short intermediate third conductive portion 14. , which extends perpendicular to the first and second planes, ie. in a vertical direction between a second end of the first conductive portion 13 (opposite its feed end near the antenna connection portion 12) and a first end of the second conductive portion 15, 16. The length of the third conductive portion 14 is preferably at least 2 mm ; in other words, the first plane including the first conductive portion 13 is separated from the second plane including the second conductive portion 15, 16 by at least 2 mm. The third conductive portion 14 is substantially narrower than the wide first conductive portion 13. The second and third conductive portions 14 and 15, 16, respectively, preferably have the same width.

The purpose of the second conductive portion 15, 16 is to rotate it relatively close to the first conductive portion 13 so as not to take up any unnecessary space in the second plane.

There will be some electromagnetic coupling between the first and second conductive portions 13 and 15, 16 respectively. The exact rotation of the second meander-shaped conductive portion 15, 16 must therefore be thoroughly tested. mmm '',. .n u nu I I nansza u: ucumzzvnwoaxnuuxicxvonvuavu-uzlu. : Lao-z f '' g- ¿, _ °,;:, '.. ° ...' å .. In LU depending on the actual application. The second meander-shaped conductive portion 15, 16 should not be confused with a traditional parasitic part, which would be placed 0.5-1 mm from the first conductive portion 13 without any electrical interconnection. On the contrary, the meander-shaped second conductive portion 15, 16 is galvanically connected to the first conductive portion 13 via the short vertical third conductive portion 14 and is consequently an actual part of the continuous antenna loop 11.

The distinct change of width between the first conductive portion 13 and the third conductive portion 14 / second conductive portion 15, 16 is electrically important because it will provide an impedance block, which will allow multi-band operation in several wide individual frequency bands.

A fourth conductive portion 17 may optionally be provided as a top load at the other end of the meandering second conductive portion 15, 16. The top load 17 in the preferred embodiment has an almost square surface which is substantially wider than the narrow mean portion. shaped second conductive portion 15, 16. If a top load is used, it is preferably arranged in the same plane (ie the second plane) as the meander-shaped second conductive portion 15, 16. The purpose of the top load 17 is to provide capacitive load of the continuous antenna loop 11 for setting purposes.

A typical electrical length of the entire antenna 11, when radiating at GSM 900 MHz, will be -2k / 5, where Ä is the wavelength in free space (33.3 cm). The typical electrical length of the antenna 11 in the 1800 MHz frequency band will consequently be approximately Ä / 5.

To further reduce the size of the antenna 11, a dielectric element may be inserted between the first and second planes, i.e. between the wide straight first conductive portion 13 and the narrow meander-shaped second conductive pair 10 15 20 25 30 35 un c n. Q ø u | ø o e ~. o n c pc DEIJSIB AR \\ CURRENT \ DB \ PuhliC \ DOC \ P \ Ll7 \ | - | J] | NL SLdOC tiet 15, 16. For clarity, such a dielectric mate-. rial only indicated by an arrow 18 in FIG. 4. For this purpose, those skilled in the art are substantially free to choose from a variety of commercially available dielectric materials.

A dielectric insert 18 between the first and second conductive portions 13 and 15, 16 will have an additional advantage in that it will provide rigidity of the antenna 11 and help prevent the first and second conductive portions from displacing from each other. Accordingly, the dielectric plug-in element 18 can be advantageously selected to have a fairly high stability, albeit not completely rigid, to allow some flexibility of the enclosed antenna 3, as indicated at positions 6 and 7 in FIG.

The antenna loop 11 is attached to a flat support element, preferably in the form of a dielectric caption film (polyamide film). In the preferred embodiment, a caption film referred to as R / Flex 2005K having a thickness of 75 pnz and commercially available from Rogers Corporation, 100 N, Dobson Road, Chandler, AZ-85224, USA is used. Alternatively, a similar dielectric film may be used as e.g. provided by Freudenberg, Mectec GmbH & KG, Headquarters, D-69465 Wein-Circuit Materials Division, heim / Bergstrasse, or any other suitable commercially available dielectric film.

The loop 11 of conductive material and the kapton film together form a flex film.

To protect the continuous antenna loop 11, it is preferably enclosed in a rubber or plastic housing 3. DRYFLEX 502670 SEBS 67 Shore A from Nolato Elastoteknik AB, Box 51, SE-662 22 ÅMÅL, Sweden, is an example of a suitable material for the housing . A suitable thickness for the casing can e.g. be about 1-2 mm.

The first embodiment shown in Figs. 3-5 is a small and efficient antenna, which provides good resonance. P \]. B? || -Ul ° 41 SEJIOC -.. ° ». -.. -». - ~ u nans performance in several different frequency bands, this is illustrated by a Smith diagram in FIG. FIG 15. Both of these diagrams are the results of simulations rather than measurements made on a real antenna.

A computer simulation program called IE3D, distributed by Zeland Software Inc., USA, has been used for the simulations.

The simulations have been performed without any rubber or plastic casing to protect the continuous antenna loop 11.

Furthermore, not a complete mobile phone but only a rectangular printed printed circuit board 10, no real antenna connection part 12 and no dielectric material 18 have been used. Thus, particularly with respect to the reflection attenuation diagram in FIG. 15, the resonant frequency ranges therein do not exactly correspond to the desired frequency ranges in actual applications. The simulated antenna consequently shows optimal resonance for frequencies located at slightly higher frequencies than the desired frequency bands, which are: EGSM at 880-960 MHz, DCS at 1710-1880 MHz, PCS at 1850-1990 MHz, UMTS at 1920 -2170 MHz and ISM / Bluetoothø at 2400-2500 MHz. The reason for this is to compensate for losses, which are introduced by a rubber or plastic casing such as DRYFLEX. The housing will lower the resonant frequencies and also introduce certain losses, which unfortunately will reduce the antenna gain somewhat but which on the other hand will provide even greater bandwidth.

As is known to those skilled in the art, a reflection attenuation diagram illustrates the frequencies at which an antenna operates, i.e. where the antenna resonates. The reflection attenuation diagram, presented in FIG. 15, represents the reflection attenuation in decibels as a function of frequency. The lower the dB values in a reflection attenuation diagram, the better. Furthermore, the wider the resonance the better. In a reflection attenuation diagram, the resonance is an area within which the reflection attenuation is low (a high negative value in dB). In the diagram in FIG 15, this looks like 10 15 20 25 30 E00 000 _ _ _ _ U QLL u¿1. . . . .- ''. . -. . - u - v 0 020513 YEAR \\ {URRENT \ DB \ PuhliC \ DOC \ P \ lB? N-UXNI SE-dot LH as a steep and deep cavity. Reflection attenuation is a parameter, which indicates how much energy the antenna will reflect or accept at a given frequency.

Reflection attenuation (RL) can be defined as: RL = -20-lg [abs (F)], where F = (reflected voltage or current) / (incident voltage or current).

A similar chart is SWR (Standing Wave Ratio).

SWR is defined as the ratio between maximum voltage or current and minimum voltage or current.

Smith diagram is a well-known tool in the art and is described in detail in the literature, e.g. in Chapters 2.2 and 2.3 of "Microwave Transistor Amplifiers, Analysis and Design", by Guillermo Gonzales, Ph.D., Englewood Cliffs, NJ 07632, USA, ISBN 0-13-581646-7. reference is also made to "Antenna Theory - Analysis and Present-Hall, Inc., Hennes", Balanis Constantine, John Wiley & Sons Inc., ISBN 0471606391, 57-59. Both of these books are fully incorporated herein by reference. Smith Diagrams, pages 43-46, are consequently not penetrated in any detail herein.

The Smith diagrams in this specification, however, briefly illustrate the input impedance of the antenna: Z = R + jX, where R represents the resistance and X represents the reactance.

If the reactance X> 0, it is referred to as inductance, otherwise capacitance.

In the Smith diagram, the curved graph represents different frequencies in an increasing sequence. The horizontal axis of the diagram represents pure resistance (no reactance).

Of particular relevance is the point at 50 (2), which normally represents an ideal input impedance. The upper hemisphere of the Smith diagram is referred to as the inductive hemisphere. The lower hemisphere is similarly referred to as the capacitive hemisphere. 10 15 20 25 30 35 uausxa AR vcunncnnosuvuuxxcxoocxvxzevu-nmui: mm 2 3 2 J .. '..' - A second embodiment of the antenna 21 according to the invention is shown in Figs. Accordingly, the antenna connection portion 22 of Figs. 6-8 is substantially identical to the antenna connection portion 12 of Figs. 3-5, the first conductive portion 23 of Figs. 6-8 being substantially identical to the first conductive portions 13 of Figs. 3-5. etc. The main difference between the first and second embodiments is the layout of the optional capacitive top load 17/27, which is significantly smaller in the second embodiment than in the first embodiment. the trout shape is illustrated in the reflection attenuation diagram in FIG. 15 and in a Smith diagram in FIG.

A third embodiment of the antenna 31 according to the invention is shown in Figs. 9-11. Similar reference numerals in FIGS. 9-11 denote similar components in FIGS. 3-5. Accordingly, the antenna connection portion 32 in Figs. 9-11 is substantially identical to the antenna connection portion 12 in Figs. 3-5, the first conductive portion 33 in Figs. 9-11 is substantially identical to the first conductive portion 13 in Figs. 3-5, etc. The main difference between the third embodiment and the first embodiment is that the third embodiment has no capacitive peak load. Simulated performance of the third embodiment is illustrated in the reflection attenuation diagram in Fig. 15 and in a Smith diagram in Fig. 18. Fig. 19 illustrates circular polarization gain versus frequency for the third embodiment, while Fig. 20 illustrates linear polarization gain versus frequency and Fig. 21 illustrates activity. These drawings represent all simulated data.

All in all, the first, second and third embodiments are similar in design and performance.

A fourth embodiment of the antenna 41 according to the present invention is illustrated in FIGS. 12-14. Compared 10 15 20 25 30 0'5. . . . . . . . . . 1 (JL C110 O 044 Ysæræzs 0205)! AR \\ CURRENT \ DB \ PublÅCUNCVNLGTN-DLUI SE-dnc uu I a o u u a ø | ø e o. I O I n! LS with the foregoing embodiments, the fourth embodiment 41 has a difference in that its meander-shaped second conductive portion 45, 46 has a slightly different layout. In addition, a small copper plate 48 is attached to a portion of the meander-shaped second conductive portion 45, 46. More specifically, the copper plate 48 is positioned to provide a short circuit between two adjacent rotations of the meander 46. This will shift the resonant frequencies and allow adjustment to desired frequency bands. Actual measurements, in contrast to simulated performance, have been made for the fourth embodiment in FIGS. 12-14. Fig. 22 illustrates a SWR diagram of the fourth embodiment when held in free space. Fig. 23 illustrates a corresponding Smith diagram. In the diagrams in FIGS. 22 and 23, values at 5 different frequencies are indicated as markers 1-5. Figures 24 and 25 illustrate inversely measured antenna performance of the fourth embodiment when held in a talking position.

The antenna according to the fourth embodiment exhibits excellent performance in a lower frequency band, which is located in the EGSM band between 880 and 960 MHz.

The SWR diagram also shows a very broad resonant cavity in higher frequency bands, which covers important frequency bands at 1800 and 1900 MHz, as well as in fact also frequency bands at 2.1 GHz and 2.4 GHz.

To conclude, the antenna according to the invention provides not only excellent performance in a low frequency band around 900 MHz (eg for EGSM) but also in four different high frequency bands around 1800 MHz (eg DCS or GSM 1800 at 1710-1880 MHz), 1900 MHz (eg PCS or GSM 1900 at 1850-1990 MHz), 2100 MHz (e.g. UMTS, telephone System ") and 2400-2500 MHz (eg Bluetooth®, ISM - The antenna according to upp- "Universal Mobile Tea-" Industrial, Scientific and Medical "). the find is in other words a multiband antenna with coverage 10 15 20 25 30 Cfïñ J¿LL 020513 AR \\ (URRENT \ DB \ Puh1iC \ |) 0 (\ P \ lB7 \ l-0l \ 01 SE-dnt undan Öfï fi _. H oÅÄ7 ÉÉÉ f: ':: nu "lb oono. O» o ø uopo of a very wide frequency band, which will be referred to further below.

Studies and experiments have shown that, above all, the geometrically wide first leading portion 13/23/33/43 generates the wide high band resonance, which is indicated in the diagrams. A standing wave is obtained with a high impedance around the second end (opposite the feed end 12) of the first conductive portion (the feed strip) 13. Conversely, above all, the meander-shaped second conductive portion 15, 16 provides good performance for the low frequency band. The rotation of the second conductive portion 15, 16 further adds inductive impedance to the antenna structure 11. This causes an impedance conversion in that the narrowly twisted second conductive portion 15, 16 is considered, at high frequencies, to have a very high impedance but a desired low impedance, about 50 (2) in the low frequency band. The connection 14 between the wide supply strip 13 and the narrow twisted portion 15, 16 consequently functions as a kind of impedance converter.

It has also been discovered that the bandwidth of the high frequency band (s) can be controlled by the width of the first conductive portion (wide feed strip) 13. The bandwidth of the high frequency band (s) increases with increasing width of the first conductive portion 13, up to a certain limit.

An important aspect of the antenna according to the invention is that it does not need a well-defined electrical ground in contrast to certain known antennas.

Another important advantage of the present invention is that it allows a very low manufacturing cost. A further advantage is that it allows reduced antenna size compared to previously known solutions, and that it is self-matching to the desired impedance (eg 50)). 10 l5 20 q. , ø Q n n u n | The present invention has been described above with reference to a preferred embodiment together with three alternatives. Many other embodiments, which are not are described herein, however, are likewise possible within the scope of the invention, as defined by the appended independent claims. jas carefully depending on the actual application.

Furthermore, the frequency bands in which the antenna operates can also vary widely depending on the actual application. The antenna loop must therefore be set for the actual application, which, however, is believed to be nothing more than a purely routine measure for a person skilled in the art and which therefore does not require any further explanation here. Although at least at present it is preferred that the first conductive portion (the wide feed strip) has a rectilinear (straight) extent, it may be possible, in other embodiments, to design the first conductive portion with a curve shape.

Claims (25)

10 15 20 25 30 35 - u - - nu 020513 AR E = \ PUBLI (\ DOC \ P \ LB7'4-Ul'l] | SE nya krawdoc u Q ~ an ~ øou 0 0 |. «. Fo; - o - ø: nc PATENT REQUIREMENTS A multiband antenna for use in a portable telecommunication apparatus (1), the antenna comprising a continuous loop (11) of conductive material, the conductive loop having a first conductive portion (13) arranged in a first plane and a second conductive portion (15-16) arranged in a second plane, which second plane is different from the first plane, the first conductive portion has a supply end (12) to be connected to radio circuit system (9) in the portable telecommunication apparatus, characterized by that the first conductive portion (13) and the feed end (12) have a distinctly larger width than the second conductive portion (15, 16) The antenna of claim 1, wherein the first conductive portion (13) has a rectilinear extent, while the second conductive portion (15-16) is meander-shaped. An antenna according to claim 2, wherein the first plane is parallel to the second plane and wherein the continuous loop (11) has a third conductive portion (14), which interconnects the first conductive portion (13) with the second conductive portion. (15-16) and which is not parallel to the first and second planes. The antenna of claim 3, wherein the third conductive portion 14 has a width that is substantially equal to the width of the second conductive portion (15-16). The antenna of claim 4, wherein the third conductive (14) is a conductive portion (13) opposite its feed end (12) and the portion is connected between a second end of the first first end of the second conductive portion (15-16). ) and wherein the third leading portion extends perpendicularly between the first and second planes. 10 15 20 25 30 35 v I> | aa An antenna according to claim 3, wherein the distance between the first and second planes is at least 2 mm. An antenna according to any one of claims 4-6, wherein the continuous loop (11) has a fourth conductive portion (17) connected to a second end of the second portion (14), opposite its first end, the fourth - forming portion is wider than the other portion and produces capacitive load on the antenna. An antenna according to claim 7, wherein the fourth conductive portion (17) is arranged in the second plane. The antenna of claim 1, wherein the width of the first conductive portion (13) is at least 5 mm. The antenna of claim 1, wherein the first conductive portion (13) has a waveform. An antenna according to claim 1, wherein the radio circuit system (9) of the portable telecommunication apparatus 1 is provided on a printed printed circuit board (10), provided with a vertical distance from the printed printed circuit board. and wherein the continuous loop (11) An antenna according to claim 11, wherein the vertical distance is of the order of 5-10 mm. The antenna of claim 11, further comprising an antenna (12) the first conductive portion (9). tin connection part for connecting the supply end of (13) to the radio circuit system The antenna of claim 1, wherein the continuous loop (11) has a thickness of about 30-35pnL 10 15 20 25 30 35 522 020513 AR E = \ PUBLIC \ DOC \ P \ L57 * 0-U] | N1 SE new requirements.d0C u - | . . . -. e u. The antenna of claim 1, wherein the conductive material for the continuous loop (11) is copper. The antenna of claim 14, wherein the continuous loop (11) is provided on a flexible dielectric support member. The antenna of claim 16, wherein the flexible dielectric support member is a caption film. An antenna according to claim 16 or 17, wherein the loop 11 of conductive material and the flat dielectric support element form a flex film. Antenna according to any one of the preceding claims, provided with a plastic or rubber housing. An antenna according to any one of the preceding claims, further comprising a dielectric member (18) disposed between the first and second conductive portions (13, 15-16). An antenna according to any one of the preceding claims, wherein the antenna is adapted to operate in at least three frequency bands. The antenna of claim 21, wherein the antenna is adapted to operate in at least three of the following: a first frequency band at about 900 MHz, a second frequency band at about 1800 MHz, a third frequency band at about 1900 MHz, a fourth frequency band at about 2100 MHz and a fifth frequency band at about 2400 MHz. An antenna according to any one of the preceding claims, wherein it is a factor of 1:10 in difference in width between the second 10 nn on IIOI a neusza AR E: \ Pus | .1c \ |> oc \ | = \ 1.a1u -n1.ux s: nya krm / mac I i I '--'- 2--' - '-2-- 9.! HD leading party (15-16) and the first leading party _ (l3); A portable telecommunication apparatus (1) for use in a wireless telecommunication system, comprising an antenna according to any one of the preceding claims. A portable telecommunication apparatus according to claim 24, wherein the apparatus is a mobile telephone (1).